1. Field of the Invention
The present invention relates to a surface-mounted antenna apparatus, more specifically, to a small and inexpensive surface-mounted antenna apparatus, which is adapted to be effectively used in electronic devices such as a television, a radio, or a wave clock for receiving radio waves.
2. Description of the Prior Art
Generally, an antenna apparatus to receive radio waves of ground digital waves or the like is required in a television, a radio and so on. An antenna apparatus to receive standard radio waves for correcting automatically a time is also used in a wave clock.
In recent, such a wave clock is used in a time piece such as a wrist watch, a clock, as well as, a various of information devices such as a mobile phone, a car navigation, a personal computer, a PDA (Personal Digital Assistant) or the like, to indicate an accurate time constantly.
The antenna apparatus used in these television, radio, wave clock, mobile phone or the like has been mainly formed into a surface-mounted type which is surface-mounted on a circuit substrate disposed within the information device or the like, because the television, the information device and so on have been miniaturized, in particular, thinned.
However, if the information device or the like is thinned, parts and so on, constituting the antenna apparatus must be distributed individually on a two-dimensional surface of the circuit substrate, even if the antenna apparatus can be thinned, there is a problem that considerable time and effort are taken in assembling the parts such as a work for connecting the parts and therefore it becomes expensive.
Accordingly, it is required to make a surface-mounted antenna apparatus, which can be thinned as a whole, is inexpensive, and is easy to assemble parts.
A typical example of a conventional surface-mounted antenna apparatus applied to a wave clock is illustrated in FIGS. 10 and 11.
The antenna apparatus 1 includes an antenna body 9, a synchronous chip condenser 2 constituting a receiving circuit or resonant circuit for receiving radio waves in association with the antenna body 9, a crystal oscillator 3 for generating a clock signal with a predetermined frequency, an IC 4 constituting a clock for forming times by the clock signal from the crystal oscillator 3 and condensers 5 and 6 for the IC 4, as shown in FIGS. 10 and 11.
In addition, the IC 4 drives the crystal oscillator 3 and the receiving circuit for receiving the radio waves and comprising the antenna body 9 and the synchronous chip condenser 2 by means of a power applied from a battery 7, corrects the times of the clock by standard radio waves received from the receiving circuit and outputs a clock signal 8 of the corrected times (see FIG. 10).
The antenna body 9 is provided with a bar-like ferrite core (not shown) for receiving the standard radio waves, and a coil 10 is wound on an outer periphery of the core (see FIG. 10). Flanges 11 and 12 are provided on opposite ends of the antenna body 9. Leads 13 and 14 of the coil 10 are directly connected with a circuit pattern 16 formed on a circuit substrate 15 in an information device, or connected through coil connecting electrodes (not shown) disposed on the flange 11 or 12 with the circuit pattern 16, as shown in FIG. 11.
Moreover, the parts such as the synchronous chip condenser 2, the crystal oscillator 3, the IC 4, the condensers 5 and 6 and so on are mounted on the circuit pattern 16 formed on the circuit substrate 15 so that a clock device is generally formed, which corrects automatically the time of electronic devices by receiving the standard radio waves and then outputs the clock signal for the corrected times (see FIG. 10).
However, because the circuit substrate 15 is provided with the circuit pattern 16 for connecting the antenna body 9, the chip condenser 2, the crystal oscillator 3, the IC 4 and so on, a space is required to form the circuit pattern 16 on the circuit substrate 15, in the conventional antenna apparatus 1 as shown in FIG. 11. In addition, at least antenna body 9 and the chip condenser 2 must be separately mounted at any position on the circuit pattern 16.
Further, a check about whether or not the receiving circuit comprising the surface-mounted antenna body 9 and the chip condenser 2 synchronizes completely with a frequency of the standard radio waves to be received cannot be performed before the completion of assembly at which the various parts such as the crystal oscillator 3 and so on have been mounted on the circuit pattern. Consequently, it takes a considerable time for carrying out the checking, the other hand, if there is a defective product on the antenna apparatus 1, time and effort are required for disassembly of the parts, re-assembly thereof and adjustment of the parts.
Moreover, in the antenna apparatus 1 as described above, because the antenna body 9 having the bar-like ferrite core is used, the antenna body 9 has a high directivity and therefore if the antenna apparatus 1 is used in a small mobile information device for communicating information at any places, sensibility of the antenna apparatus 1 largely varies in the use of only one antenna body 9, because directions of communicating information in the antenna apparatus 1 vary pursuant to a posture of the antenna body 9. As a method avoiding the variation in the sensibility of the antenna apparatus, it is known to receive radio waves or a signal by arranging to be approximately perpendicular two antenna bodies to form a more-high sensitive antenna apparatus (for example, Japanese Patent Laid-Open 2002-272482).
However, as described above, when the two antenna bodies are arranged perpendicularly and used, although the variation in the sensibility of the antenna bodies can be prevented, the antenna apparatus becomes more expensive, because the antenna bodies and the condensers for consisting the receiving circuit in synchronization with the antenna bodies must be disposed at least two by two, a wide space is required to dispose the plurality of antenna bodies and the condensers, ant therefore it is not avoided that the information device becomes a large size.